Disk type rotor for axial pole induction motors



Sept. 21, 1948. L. E. ASKE 2,

DISK TYPE ROTOR FOR AXIAL POLE INDUCTION IOTORS Filed June 25, 1946INVEN7'0R.'- LEONARD ASKE Patented Sept. 21, 1948 I DISK TYPE ROTOR FORAXIAL POLE INDUCTION MOTORS Leonard E. Aske, Minneapolis, Minn.,assignor to General Mills, Inc., a corporation of Delaware ApplicationJune 25, 1946, Serial No. 679,073 9 Claims. (Cl. 172-120) This inventionrelate induction motors.

An object of the invention is to improve and simplify the rotors forshaded pole induction motors disclosed in my patent application, SerialNo. 659,217, filed April 3, 1946, entitled Shaded pole induction motor.

This and other objects, as will hereinafter appear, are accomplished bythis invention which is fully described in the following specificationand shown in the accompanying drawing, in which Figure 1 is a top plan.view of a rotor embodying my invention; and

Fig. 2 i a transverse section on the line 2--2 of Fig. 1.

The embodiment illustrated comprises a flatcup-like member I D ofnon-magnetic material, preferably copper, having a nearly flat bottom I2and an upstanding cylindrical ring l4.

Withinthis member is housed a spider I'G of magnetic material,preferably sheet steel, having a serie of notches I8 forming lobes 20,the outer portions of which are circular. The notches I8 are preferablyone-half the peripheral diameter of the spider.

Steel buttons 22 having a radius equal to that of the outer portion ofthe lobes 22 are secured thereto in any suitable manner, as disclosed inmy co-pending patent application mentioned above. In the presentinstance they are preferably spot welded thereto.

Above the spider member 2!! lie other spider members 30 which areidentical in'periphery with the spider 20 but which do not have anybuttons secured thereto. A stepped bushing 34, preferably of stainlessteel, is inserted through central openings in the bottom I! and in thespider member 20, which openings are of the same size but are larger indiameter than the openings in the spider membersSll so that a shoulder36 On the steel bushing has a bearing on the lowermost member 30.

.The cup-like member I is closed at the top by means of a copper disk 40which fits snugly over the top of the bushing 34. A serie of openings44, 46 are formed in the bottom I! and in the top disk 40 in alignmentwith the inner ends of the notches l8 for the reception of copper pinsor rivets 50 which may be fed through these holes and through thesenotches in any suitable manner. This may be done by passing a serie ofcopper rods through these openings, which rods are then cut to suitablelengths in any desired manner or the rods or rivets 50 may be preformedand passed down through these openings, after to rotor for shaded poleon the one hand andthe copper members I2 and 40 on the other. Also, theupper edge of the cup I4 i forced into intimate contact with theperiphery of the disk 40. At the same time the lower outer edge of thebottom I2 may be inclined upwardly somewhat, as indicated by the letterE, which is preferably set at an angle of 2 to the bottom.

Thus an intimatebond is formed between the ends of. the rivet 50 and themetal plates [2 and 40 which insures a path of low resistance forelectric current which is induced in these rivets as they are caused toout through line of force in the field of the shaded pole inductionmotor in which this rotor isbeing used. Thus a heavy starting andrunning torque is provided in this rotor which may be employed in thetype of shaded pole induction motor illustrated in the I patentapplication above referred to.

To insure a more permanent electrical connection between ends of therivets 50 and the sheath members consisting of the bottom l2 and disk40, I have sometimes dipped the rotor in melted solder. This also adds aprotective coating to the rotor.

It will thus be seen I have provided a very simple and efficient type ofrotor for an induction motor and one which can be produced at low cost.

While I have shown and described but'a few embodiments of my invention,it is to be understood that it is capable of many modifications.Changes, therefore, may be made which do not depart from the spiritand'scope of my invention as disclosed in the appended claims.

I claim as my inventionf 1. A disk type rotor for an axial poleinduction motor comprising a plurality of rotor sections of magneticmaterial each made up of a series of radiating lobes separated by deepindentations, a copper sheath substantially enclosing the rotorsections, and a rivet extending through the sheath at the bottom of eachindentation electrically connecting the two faces of the-sheath andfirmly securing the sheath to the rotor sections, the magnetic materialextending through openings in one of said faces of the i sheath.

2. A disk type rotor for an axial pole induction motor comprising aplurality of rotor sections of magnetic material each made up of aseries of radiating lobe separated by deepindentations, a copper sheathsubstantially enclosing the rotor sections, and a rivet extendingthrough the sheath at the bottom of each indentation electricallyconnecting the two face of the sheath and firmly securing the sheath tothe rotor sections, the lowermost rotor section having a steel buttonsecured to the outermost surface of each lobe and extendingsubstantially through an opening in the sheath. 1

3. A disk type rotor for an axial pole induction motor comprising aplurality of rotor sections of magnetic material each made up of aseries of radiating lobes separated by deep indentations, a

copper sheath substantially enclosing the rotor sections, a rivetextending through the sheath at the bottom of each indentationelectrically connecting the two faces of the sheath and firmly securingthe sheath to the rotor sections, the lowermost rotor section having asteel button secured to the outermost surface of each lobe and extendingsubstantially through an opening in the sheath, and a steel bushingextending centrally through the rotor.

4. A disk type rotor for an axial pole induction motor comprising aplurality of rotor sections of magnetic material each made up of aseries of radiating lobes separated by deep indentations, a coppersheath substantially enclosing the rotor sections, a rivet extendingthrough the sheath at the bottom of each indentation electricallyconnecting the two faces of the sheath and firmly securing the sheath tothe rotor sections, the lowermost rotor section having a steel buttonsecured to the outermost surface of each lobe and extendingsubstantially through an opening in the sheath, and a stepped steelbushing extend ing centrally through the rotor.

5. A disk type rotor for an axial pole induction motor comprising aplurality of rotor sections of magnetic material each madeup of a seriesof radiating lobes separated by deep indentations, a non-magneticcurrent-carrying metal sheath sub-' 4 stantially enclosing the rotorsections, and a rivet extending through the sheath at the bottom of eachindentation electrically connecting the two faces of the sheath andfirmly securing the sheath to the rotor sections, the magnetic materialextending through openings in one of said faces of the sheath.

6. A disk type rotor for an axial pole induction motor comprising acup-shaped member of non-magnetic electrically conducting material.having a bottom plate and a cylindrical side wall section. a pluralityof laminations of magnetic material in said member having radial lobesseparated by notches, a cover plate of electrically conducting materialoverlying said laminations at the opposite end of said member from saidhottom plate, and an electrically conducting retaining member extendingaxially through the inner end of each notch and fastened to said bottomand cover plates.

7. A rotor according to claim 6 in which one of said plates has anopening aligned with each lobe.

8. A rotor according to claim 6 in which one of said plates has anopening aligned with each lobe, and one lamination carries a. button ofmagnetic material on each lobe, said buttons extending through saidopenings.

9. A rotor according to claim 6 in which said cover plate iselectrically connected to said cylindrical side wall.

LEONARD E. ASKE.

REFERENCES CITED The following references are of record in the tile ofthis patent:

UNITED STATES PATENTS Number Name Date 428,650 Thomson May 27, 18901,933,498 Morrill Oct. 31, 1933 2,004,866 Haldeman June 11, 19352,246,777 Bordeaux et al June 24, 1941 2,247,489 Gottlieb July 1, 19412,316,960 Ingersoll Apr. 20, 1943 2,387,073 Horlacher Oct. 16, 1945

